Collaborative Research: Linking Permafrost Soil Inundation to Carbon and Mercury Uptake in Aquatic Food Webs of the Arctic

合作研究：将永久冻土淹没与北极水生食物网中碳和汞的吸收联系起来

• 批准号: 2211427
• 负责人: Elchin Jafarov
• 金额: $ 13.8万
• 依托单位: Woodwell Climate Research Center, Inc.
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2211427&HistoricalAwards=false
• 关键词: Collaborative; Research; Linking; Permafrost; Soil

The element mercury is a common global contaminant released from human activities that impact both environmental and human health worldwide. One form of mercury, methylmercury, is produced by microorganisms in a process called mercury methylation and can accumulate to toxic levels in aquatic organisms across the food web. Permafrost soils of the Arctic contain large stores of ancient mercury that are also being released to freshwater and coastal marine environments from thawing soils due to a warming Arctic. Women and children in rural communities in the Arctic that rely on subsistence fishing are most vulnerable to the toxic effects of mercury. The central questions surrounding mercury in the Arctic are the relative importance of ancient mercury released from thawing permafrost soils versus newer mercury from the atmosphere, and how rapidly changing conditions in Arctic landscapes will affect the transformations and food web uptake of these different sources of mercury. To address these questions, this study will use multiple approaches to track the releases, transformations, and uptake of both carbon and mercury from permafrost soils to aquatic ecosystems and subsequently to resident fish. The project further aims to develop a practical approach to model the potential for important mercury transformations in lakes and ponds with underlying permafrost soils. Through dialogue with rural communities in Arctic Alaska, we will share what we learn with people who are heavily impacted by mercury pollution. We will also help train the next generation of scientists working on these problems.The study will be carried out using a series of expanding thermokarst lakes and recently formed beaver ponds in U.S. National Park Service lands in northwest Alaska. First, field studies will target the microbial methylation of permafrost mercury and its dependence on permafrost carbon using metagenomics, field experimentation, and measurements of carbon respiration pathways. Next, the uptake of permafrost carbon and mercury in aquatic food webs will be quantified using a combination of radio and stable isotopes (carbon, mercury, nitrogen, and sulfur) and isotope mixing analyses. Isotope mixing models aim to differentiate ancient versus contemporary mercury and carbon in Arctic food webs. The goal is to establish a process-level understanding of the mobilization, microbial transformation, and biotic uptake of carbon and mercury from permafrost soils to aquatic food webs. Lastly, field observations will inform modeling efforts of lakes and ponds to establish linkages between thermal and biogeochemical regimes of water bodies and mercury methylation. This combination of process-level science and predictive model development will provide the necessary information to understand mercury cycling in Arctic systems under present and future conditions. The research findings will be communicated to rural communities in Arctic Alaska through participation in Subsistence Resource Council meetings, to the general public through public presentations and media in collaboration with a science communication specialist at the U.S. National Park Service, and to the scientific community through conference workshops and peer-reviewed journal articles. Undergraduate, graduate, and postdoctoral researchers will cross-train with collaborators across institutions and participate in outreach activities, to develop a diverse and globally competitive STEM workforce to address future environmental challenges beyond this project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

元素汞是从人类活动中释放出的一种常见的全球污染物，影响了全球环境和人类健康。一种称为汞甲基化的过程，一种形式的汞，甲基马汞是由微生物产生的，可以在整个食物网中的水生生物中积累到有毒水平。北极的多年冻土土壤中包含大量的古代汞储藏，这些汞也因北极变暖而从融化的土壤中释放到淡水和沿海海洋环境中。北极农村社区的妇女和儿童依靠生存捕鱼最容易受到汞的毒性影响。北极汞围绕汞的中心问题是，从融化的多年冻土土壤与大气中的较新汞中释放的古代汞的相对重要性，以及北极景观中的条件迅速变化将影响这些不同汞来源的转化和食物网络吸收。为了解决这些问题，这项研究将使用多种方法来跟踪从多年冻土土壤到水生生态系统以及随后再到居民鱼类的碳和汞的释放，转化和吸收。该项目进一步旨在开发一种实用方法，以模拟具有深层土壤潜在的湖泊和池塘中重要的汞转化的潜力。通过与阿拉斯加北极的农村社区进行对话，我们将与受到汞污染影响重大的人分享我们所学的知识。我们还将帮助培训从事这些问题的下一代科学家。该研究将使用一系列扩展的Thermokarst湖泊进行，最近在阿拉斯加西北部的美国国家公园服务地上成立了海狸池塘。首先，现场研究将使用宏基因组学，野外实验和碳呼吸途径的测量值靶向永久冻土汞的微生物甲基化及其对多年冻土碳的依赖。接下来，将使用无线电和稳定的同位素（碳，汞，氮和硫）以及同位素混合分析的组合来量化水生食物网中的多年冻土碳和汞的吸收。同位素混合模型旨在区分北极食品网中的古代汞与碳和碳。目的是建立对动员，微生物转化以及从多年冻土土壤到水生食物网的碳和汞的生物吸收的过程级别的理解。最后，现场观察将为湖泊和池塘的建模工作提供信息，以建立水体的热和生物地球化学方案与汞甲基化之间的联系。过程水平科学和预测模型开发的这种结合将提供必要的信息，以了解当前和未来条件下北极系统中的汞自行车。研究结果将通过与美国国家公园服务局的科学传播专家合作，通过公众演讲和媒体合作，通过公众介绍和媒体通过会议研讨会以及会议研讨会和同行评审的期刊文章将研究结果通过公众演讲和媒体进行传达给阿拉斯加北极的农村社区。本科生，毕业生和博士后研究人员将与机构的合作者进行交叉培训，并参与外展活动，以开发多样化且具有全球竞争性的STEM劳动力，以应对该项目以外的未来环境挑战。本奖奖反映了NSF的立法使命，并被视为通过基金会的智力效果和广泛的评估来评估，并值得通过评估来进行评估。